Here’s a fun, hands-on activity that uses paper “light bulbs” to introduce binary (bi- = 2), the number system with only two numbers, 0 and 1. Aimed at upper elementary, I’ve also taught this binary lesson to students as young as first grade by slowing the pace. Binary is the language used by computers—they run on electricity, which can only be on or off (O or 1).
Students will contrast the place value for the decimal system (1, 10, 100, etc.) with the binary place value (1, 2, 4, etc.) Directions for each student to make five paper light bulbs and a binary place value chart are clearly explained, including what’s needed (just paper, scissors, pencil, ruler).
Each student draws and labels 5 cartoonish light bulbs on paper squares (one side: off = 0, other side: on = 1) and makes a simple place value chart with five columns, labeled from 1 to 16. This is shown step-by-step with diagrams.
Using their paper light bulbs, students figure out how to create binary numbers by “turning on” certain ones. They start with their light bulbs all turned off (that’s 0) on the chart. To make a 5, for instance, they “turn on” (that is, turn over) light bulbs needed to add up to 5. Since 4 + 1 = 5, students turn the bulbs in the 4s and 1s place value columns so that the on = 1 side is up. They just read the number on the light bulbs. A binary 5 is “on, off, on,” so it looks like this: 101.
More binary practice follows. After that, challenge your students to figure out higher binary numbers by adding more bulbs and place value columns. Ask, “How would you write 50? 97? 351?”
In a 4th/5thcombo class, we turned a refrigerator box into a binary machine. A student hid inside and guests wrote a number from 1 to 128 through a slot. The student quickly figured out the binary number and pushed it through a slot on the other side. Hilarious.
Once students understand binary (0,1), they can check out other number systems, such as the 3s (0, 1, 2) or 7s (0, 1, 2, 3, 4, 5, 6). Will paper light bulbs work for other systems? (No—a binary light bulb only has two sides, one side to represent 0 and the other side to represent 1!)